1. Field of the Invention
This invention relates to a spiral cable reel made up of a flat cable, which is used, for instance, for electrically connecting a stator member to a rotor member in case where a vehicle such as an automobile is equipped with an air bag system; and more particularly to a spiral cable reel of a type that is designed to temporarily stop the relative rotation between the rotor member and the stator member when it is installed on the vehicle body.
2. Related Art
Heretofore, for instance in installing an air bag system in a vehicle such as an automobile, a spiral cable reel is employed in which the stator member and the rotary member are electrically connected through a flat cable. In connecting the spiral cable reel to equipment such as a steering wheel, it is essential that the rotor member is turnable from the neutral position of the steering wheel both right and left to the same extent (about 2.5 to 3 turns). For this purpose, in general, a locking mechanism is widely employed for the cable reel, which correctly determines the positional relationship between the stator member and the rotor member and holds it unchanged. One example of the locking mechanism for the cable reel has been disclosed by Japanese Utility Model Kokai Publication No. 86980/1990.
Another example for correctly determining the positional relationship between the stator member and the rotor member and holding it unchanged is illustrated in FIG. 11. FIG. 11 is a perspective view showing a stopper which is adapted to temporarily stop the relative rotation of the stator member and the rotor member of the spiral cable reel. In FIG. 11, reference numeral 1 designates the stator member; and 2, the rotor member which is rotatably mounted with respect to the stator member 1. A spiral cable (not shown) is accommodated inside the rotor member 2 to form the spiral cable reel in combination with the stator member 1 and the rotor member 2. Further in FIG. 11, reference number 3 designates the stopper; 4, a positioning pin (or so-called "locate pin") provided at a predetermined position on the rotor member 2. When installed, the positioning pin 4 is fitted in an engaging hole formed in the steering wheel. Further in FIG. 11, reference numeral 5 designates an upright pillar provided at a predetermined position on the stator member 1; 6, a locking hole formed in the stopper 3, to engage with the positioning pin 4; and 7, a locking hole formed in the stopper 3, to engage with the upright pillar 5.
In order to correctly position and hold the stator member 1 and the rotor member 1 until the spiral cable reel is coupled to a body of the vehicle, the relative rotation of the stator member and the rotor member is temporarily suspended such that the locking hole 6 of the stopper 3 is engaged with the positioning pin 4 of the rotor member 2, while the engaging hole 7 of the stopper 3 is engaged with the upright pillar 5 of the stator member 1. Thereafter, in coupling the spiral cable reel to equipment such as a steering wheel, the stopper 3 is first removed with a predetermined external force to thereby eliminate the prevention of the relative rotation of the stator member 1 and the rotor member 2, and then the positioning pin 4 of the rotor member 2 is fitted in the engaging hole (not shown) of the steering wheel.
As was described above, in the spiral cable reel shown in FIG. 11, the relative rotation of the stator member 1 and the rotor member 2 is temporarily suspended with the stopper 3. Hence, in coupling the spiral cable reel to equipment such as a steering wheel, it is necessary to remove the stopper 3 by application of an external force thereby to eliminate the prevention of the relative rotation of the stator member 1 and the rotor member 2 before the coupling between the spiral cable reel and the equipment is completely finished. Hence, there is a high possibility that the rotor member 2 may turn during the reel coupling work. This turn of the rotor member 2 may give rise to the following problems:
(1) Adjustment must be so made that the positioning pin 4 of the rotor member 2 is correctly fitted in the engaging hole (not shown) of the steering wheel during the reel coupling work. PA1 (2) If the positioning pin 4 of the rotor member 2 is fitted in the engaging hole (not shown) of the steering wheel at a position other than the predetermined neutral position (or "N" position) and the steering wheel is turned, then the flat cable (not shown) in the spiral cable reel may be broken. PA1 a stator member; PA1 a rotor member mounted in such a manner that the rotor member is rotatable with respect to the stator member; and PA1 a stopper for stopping the rotation of the rotor member with respect to the stator member, PA1 in which, according to the invention, PA1 a stator member; PA1 a rotor member rotatable about an axis with respect to the stator member; and PA1 stopper means temporality retained on both the stator member and the rotor member for preventing relative rotation between the rotor member and the stator member, wherein the stopper means is removed from the rotor member and the stator member upon the stopper means is moved along a plane orthogonal to the axis, to thereby permit the relative rotation between the rotor member and the stator member.
Further, in a case where the air bag system is incorporated in the equipment such as a steering wheel, the steering wheel is filled up with the unit of the air bag system, and therefore it becomes impossible to visually check the positioning pin 4 of the rotor member 2 from outside. Therefore, the above-described problems (1) and (2) are liable to occur.